Dental instrument for crown or cap holding.



J. W. IVORY. DENTAL INSTRUMENT FOB. CROWN 0R GAP HOLDING.-

APPLIOATION nun FEB. a, 1909.

Patented D60. 27, 1910.

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IVORY, OF PHILADELPHIA, PENNSYLVANIA.

JAMES W.

LET FFKQ.

DENTAL INSTRUMENT FOR GROWN 0R CAP HOLDING.

eraser.

Specification of Letters Patent.

Patented Dec. 27, 1910.

Application filed "February 5, 1909. Serial No. 476,210.

To all whom it may concern:

Be it known that I, JAMns IV. IVORY, a subject of the King of GreatBritain, residing in the city and county of Philadelphia, State ofPennsylvania, have invented a new and useful Dental Instrument for Crownor Cap Holding, of which the following is a specification.

This invention relates to an instrument for dental holding and has foran object, to produce a simple, complete and eflicient means forseparating a pair of caps used in crown work, whereby the caps mayretain the perfect contour of the tooth and after the completion of thecrown again be fitted together and correctly position the crown upon thetooth or root of the tooth as the case may be. 7

It further consists of an instrument provided with means for engagingtelescoping caps of various sizes and permitting careful and accuratemanipulation and handling of the same.

It further consists of novel details of construction all as will behereinafter set forth.

Figure 1 represents in perspective the telescoping caps of a tooth crownemployed in my invention. Fig. 2 represents a side elevation of the samein telescoped position. Fig. 3 represents a section of the same mountedon a tooth. Fig. 4: represents a longitudinal section of a noveltelescoping cap-remover embodying my invention, show ing a crown and capthereon and in dotted lines the crown removed. Figs. 5 and 6 representlongitudinal sections of modifications. Fig. 7 represents a longitudinalsection of an auxiliary expanding member. Fig. 8 represents a section online mw, Fig. 6. Fig. 9 represents a longitudinal section of a portionof the device showing the auxiliary expanding member connected with thehandle. Fig. 10 represents a section through the same wit-h a portion ofa cap remover in position.

Similar numerals of reference indicate corresponding parts in thefigures.

In said drawings, I have shown an embodiment of my invention, which Ihave found operates successfully in practice, but it will be evidentthat changes therein may be made and the arrangement thereof may bevaried which will come within the scope of my invention, and I do not,therefore, desire to be limited in every instance to the exact forms asherein shown and described, but

desire to make such changes as may be necessary.

Referring to the drawings :-1 designates a cap adapted to fit over theroot or a broken tooth and form a bearing for the accurate adjusting andfitting thereon of a tooth crown. This cap 1 is preferably formed ofgold or a like material having malleable qualities in order that the capmay be accurately fitted over the tooth or root and conform readily tothe irregular configuration thereof. 2 designates a second cap adaptedto fit over and inclosc the cap 1, the two caps being proportioned togive a snug fit and allow for the telescoping action. The cap 2 is, inthepresent instance, formed of a similar material as cap 1, and itsfunction is to serve as a base for the crown proper and slide over andtelescope with the cap 1 to form a solid fastening means for the crown.

It will readily be apparent when the two caps have been positioned overa tooth or root and have been pressed to conform to the shape thereofthat some care is required to separate them without altering the formedshape. By my novel cap-removing means, I can accomplish this quickly,easily and without damage to the shape of the caps. For the purpose Ihave devised a novel instrument consisting as here shown, of acylindrical tubular handle 8 having secured at one end a plurality ofeXpansible members 4:, each preferably tapering to a comparatively smalljaw here disclosed with a knurled surface. It will be clear if the cap 1is placed over the jaws 5, and the members 4: forced to an expandedposition that the cap 1 will be gripped tightly on the interion and heldsecurely by the roughened surface preventing its withdrawal. In order toeX- pand the members at in the proper manner and as desired, Ipreferably employ a rod 6 having an enlarged head 7 thereon to cooperate with the members 4, and it will be apparent if the rod 6 ispassed through the handle 3 and forced into engagement with the membersat that the head 7 will cause the same to expand in the desired manner.The operating means for the rod 6 consists, in a preferred form, of abushing 8 detachably secured within the end of the handle 3, here shownas held stationary therein by means of screws 9, the said bushingforming a bearing for a thumb screw 10 adapted to cooperate with thethreaded end 11 of rod 6,

whereby the turning movement of the thumb screw 10 produces movement inone direction or the other of the rod (5 according to the direction inwhich the thumb screw 10 is rotated. In order to prevent a movement ofthe thumb screw 10 along the rod 6, a

head 11 is formed thereon which engages with the bushing 9 and maintainsthe thumb screw 10 in its correct position. A stop 12 is secured to therod 6 and projects into an opening 18 of the handle 3 whereby rotarymovement of the rod 6 is prevented and it will, of course, be understoodthat the opening 13 is of sutficient length to permit the necessarylongitudinal movement of the expanding rod 6.

In the modification disclosed in Fig. 5, the bushing 8 is dispensed withand the thumb screw 10 is threaded directly into the handle 3, wherebyrotation thereof operates to advance the thumb screw into the handle 3or withdraw it according to direction of movement and consequently movethe rod 6 to expanding posit-ion owing to its attachment thereto.

I11 Fig. 6, it will be noted that the rod 6 is somewhat longer than inprevious forms, and the head 7 is positioned so as to expand the jaws 5when the rod 6 is moved into the handle 3 and the threads 11 on the rodare cut with the opposite pitch in order to pro duce such movement. 1%designates a plurality of expanding members, similar to the members 4,mounted on a hub 15, which is provided with internal screw threads 16,adapted to be passed over the end of the handle 3 which may be, as shownin Fig. 6, provided with threads 17 to receive the same and thus inclosethe jaws I within an outer cylindrical set of expanding members. Thisarrangement may be used in cases of very large caps where the expandingmembers 4: as shown in the previous figures do not expand sufiicientlyto engage the inner sides of the cap 1.

In the operation of my device, the two caps 1 and 2 are placed over atooth and worked into the correct configuration, whereupon they are bothremoved and as one is closely telescoped within the other, the jaws areinserted within the cap 1 and the thumb screw 10 rotated to move the rod6 with its expanding head 7 into engagement with the members at,whereupon they are forced outwardly and grip the interior of the cap 1sufiiciently tight to permit the outer cap 2 being readily removed. Assoon as they are separated, the cap 1 is placed upon the tooth and thecap 2 then has the crown built around it, after which it may be easilyslipped back upon the cap 1 in its correct position and shape.

It has long been the desire of the bridgeworker to have an instrument toseparate the inner cap of a telescope crown from its outer cap withoutinjury to the inner cap itself. The usual method of forcing the capsapart with pliers, a piece of wood, a knife and other instruments isindeed very crude and, in many cases of tight fitting i11- ner caps,causes permanent injury by bending or otherwise mutilating the edge ofthe cap. Caps of any practical size varying from the smallest, (thosemade for a lower bicuspid) to the largest, molar telescope crowns, canbe removed and tightly held by this instrument without injury. Inperfecting this instrument every effort has been made to reduce its sizeand thus make it convenient to handle.

In order to make this instrument adjustable to all telescope caps, itwas found necessary to make an extra attachment for the large telescopecaps, although the majority of telescope crowns will range within theadjustment of this instrument without the attachment. The second part,or attachment, can be screwed over the instrument when necessary toremove the inner cap of a large telescope crown and the instrument, withits attachment, will then act on the same principle as a largerinstrument, thus saving the expense and annoyance of having twoinstruments of different sizes.

The adjustable remover and holder is, as its name implies, valuable as aholder for maintaining 01' holding firmly while adjusting, any sizecrown, cap or bridge.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is

1. In a device of the character stated, a handle, an expansible jaw atone end thereof adapted to fit into a tooth cap, a rod mounted in saidhandle and longitudinally movable therein, the end of said rod beingadapted for engagement with said expansible jaw, and a separate memberrotatably mounted on said handle and in engagement with said rod tolongitudinally move said rod when said member is rotated.

2. In a device of the character described, a handle, an expansible jawat one end thereof adapted to fit into a tooth cap, a rod mounted insaid handle and longitudinally movable therein, a head on said rod and athumb screw at the opposite end of said handle adapted to move said rodto force said head into engagement with said jaw.

3. In a device of the character described, a handle, an expansible jawcarried thereby, an auxiliary expansible member for engagement with saidjaw and fit into a tooth cap and means to expand said jaw and auxiliarymember.

r. In a device of the character described, a handle, an expansible awcarried thereby, an auxiliary expansible member detachable on said jawand adapted to fit into a tooth cap, a rod mounted in said handle, meansto shift said rod, and means on said rod to expand said jaw andauxiliary member.

5. In a device of the character stated, a handle, an expansible jaw atone end thereof, a rod mounted in said handle, and longitudinallymovable therein, the end of said rod being adapted for engagement withsaid expansible jaw, a member rotatably mounted on said handle and inengagement with 10 said rod to longitudinally move said rod when saidmember is rotated, and an auxiliary expansible member adapted forengagement with said device and adapted to receive said expansible jaw,whereby said expansible member is expanded by said ex- 15 pansible jaw.

JAMES W. IVORY.

lVitnesses:

ROBERT M. BARR, C. D. MOVAY.

